Rotary target projector



Jan. 15, 1957 w. K. M ccuRDY ROTARY TARGET PROJECTOR Filed June 9. 1954 2 Sheets-Sheet l INVENTOR. WlLLiAM K. MAC CURDY ATTORNEY Jan. 15, 1957 w; K. M CURDY 2,777,319

ROTARY TARGET PROJECTOR Filed June 9,- 1954 2 Sheets-Sheet 2 INVENTOR. WILLIAM K. MAC CURDY BY )ll @3142,

ATTORNEY costly than with prior arrangements. I present invention provides for more accurateand simplified control over impact conditions.

United States Patent O ROTARY TARGET PROJECTOR William K. MacCurdy, Menlo Park, Calif., assignor, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Application June 9, 1954, Serial No. 435,657

Claims. (Cl. 73-12) The present invention relates to apparatus for effecting controlled impact between a target and a fuze, of the kind employed in explosive munitions for causing detonation of an explosive charge upon the fuze striking the target, and has more particular reference to apparatus of the above type wherein the fuze is held stationary and the target is moved into impact therewith.

It is requisite to the efficient and successful development of impact fuzes of the kind employed in certain ordnance explosive applications that the behavior of a particular fuze, during the period of impact of fuze and target, be readily observable whereby to permit accurate assessment of the operating characteristics of the fuze under varying conditions of impact and provide for facility in determining the causes of fuze maloperation.

To these ends, various arrangements have been heretofore proposed for effecting observable impact between a fuze and target and for controlling the conditions under which such impact occurred. Such prior arrangements proved to be unsatisfactory, however, owing to fuze movement during the observation period. Thus, in the prior arrangements, the target was held in a fixed position and the fuze was, by some means, projected at the fixed target at velocities comparable to those encountered in service. Such rapid movement of the fuze rendered direct observation thereof during the period of impact extremely difli- In such prior arrangements,

havior through observation of a series of high-speed photographs, or where high-speed motion picture photography was employed, through observation of the motion picture film projected at a reduced speed. It will be appreciated, from the foregoing, that such prior arrangeto a fitting 15.

ments were complex, excessively costly to, manufacture, I

.and difiicult and time consuming to set up and use.

Moreover, it was difiicult, in such prior arrangements, to control the conditions of impact.

The present invention seeks to overcome the disadvantage inherent in the prior arrangements for providing,

observable impact between fuze and target under varied controlled conditions by providing apparatus wherein the fuze is maintained stationary and a target, carried on a rotary support, is driven to a desired angular velocity and is then caused to move into impact with the fixed fuze. Owing to the stationary disposition of the fuze, direct observation of the latter during the impact period may be had whereby the observation procedures are greatly simplified, or if a photographic recording of the impact is desired, the apparatus required and the operations involved will be substantially less complex and less Moreover, the

In accordance with the foregoing, it is an object of p ice impact between a fuze and target under varying preselected conditions of impact.

Another object of the invention is the provision of apparatus as in the foregoing wherein the fuze is held stationary and the target is projected into impact therewith whereby to render possible direct observation of the fuze during the impact period.

A further object of the invention is the provision of apparatus for causing impact between a fixed fuze and moving target wherein a rotary support carrying the target is, upon the target reaching a desired angular velocity, shifted in a manner to bring the target into impact with the fuze.

Still a further object of the invention is the provision of apparatus for causing impact between a fixed fuze and a moving target wherein the latter is carried by a rotary support and is, upon the support being driven to a desired angular velocity, released and follows a predetermined flight path into impact with the fuse. 7

Other objects and many of the attendant advantages of the present invention will become apparent as the same becomes better understood from the following detailed description had in conjunction with the annexed drawings wherein:

I Fig. l is a perspective View, partially in section, of one form of the present invention;

Fig. 2 is an enlarged sectional view of the drum cam arrangement for causing axial translation of the rotary target support of Fig. 1;

Fig. 3 is a perspective view of a modified form of the present invention;

Fig. 4 is an enlarged detail view of the target notching mechanism for effecting tangential release of the targets from the rotary target support of Fig. 3; and

. Fig. 5 is a cross-sectional view taken along the line 5-5 of Fig. 4. I

Referring now to the drawings and more particularly to Figs. 1 and 2, illustrating one physical embodiment of the present invention, 10 designates a fuze whose behavior during impact with a target 11, carried by a supporting structure 12, is to be studied. Fuze 10 is held fixed as by being mounted on a stationary structure as indicated. Target 11, which may take the form of a substantially circular plate, as illustrated, is fixedly carried on one end of an arm 14 forming a part of the supporting structure 12, the other end of which arm is secured Extending through fitting 15, at right angles to arm 14, is a shaft 16, fitting 15 being fixed to shaft 16 intermediate the ends of the latter. Extending from fitting 15, on the side thereof opposite to arm 14 and in coaxial relationship with the latter, is an arm 17 which serves to counterbalance the weight of arm 14 and target 11 whereby to achieve dynamic balancing of the device. Shaft 16 is, at its lower end, slidably and rotatably supported in a suitable bearing assembly, indicated at 18, fixed to a stationary support as indicated. A deceleration buffer assembly, comprising a suitable energy absorbing device 19 fixed to the stationary support as indicated, and operatively connected to a ring 20, slidably mounted on shaft 16, is provided for a purpose to be hereinafter described. Coaxially fixed to the upper end of shaft 16 is a drum cam 21 comprising a helical cam track 22, the pitch of which increases from its lower extremity to its upper extremity, as shown. Mounted at opposite ends of cam 21 are a pair of roller bearings 23 to the outer races of which are fixed a pair of flanged sleeve bearings 23. The outer cylindrical surfaces of sleeve bearings 23' have a diameter slightly greater than the maximum diameter of cam 21 and slidably engage the inner surface of a stationary guide sleeve 24. Sleeve 24 is rigidly fixed to a stationary supporting structure, as indicated. Pivotally mounted on sleeve 24 is a cam follower roller 25 which is adapted to be manually selectively pivoted to a disengaged position, illustrated in phantom lines, or to an engaged position, shown in solid lines, wherein the roller projects through an opening in sleeve 24 into engagement with cam track 22 for causing axial translation of shaft 16 during rotation of the latter, as will hereinafter appear. Coaxially fixed to the upper end of cam 21 is a shaft 26 having mounted on its free end one element of a clutch device 27, the other element of which is adapted to be driven in rotation by suitable driving means, not illustrated. The clutch elements may in some suitable manner, such as by magnetizing the elements, normally be held in engagement.

In operation of the above described embodiment, the parts are initially positioned with the clutch device 27 engaged and cam follower roller 25 in its disengaged position. The driving means, not shown, is energized whereby to cause rotation of shaft to, arm 14, and target 11 to a desired angular velocity. During this driving period, arm 14 rotates in a plane axially spaced above the plane in which the fixed fuze 10 is disposed, as shown in Fig. 1. Upon the shaft 16 attaining the desired angular velocity, the cam follower roller 25 is manually placed in its engaged position, shown in solid lines in Fig. 2, whereupon movement of the roller along the cam track 22 as the drum cam 21 rotates will cause axial translation of drum cam 21 and shaft 16 in a downward direction as seen in Fig. 1. The increasing pitch of the cam track 22 provides for relatively low and uniform acceleration of shaft 16 in the axial direction. Downward axial translation of shaft lficauses separation of the elements of clutch device 27, whereby the rotary parts coast for the remainder of the operating cycle. Downward axial movement of shaft 16 causes target 11 to describe a descending, substantially helical path, the arrangement of the parts being such that at a point approximately midway along such path, the target 11 will move into impact with the fixed fuze 10, as shown in Fig. 1. Shaft 16 and arm 14 will continue to freely rotate and translate downwardly until the cam follower roller 25 is cammed outwardly to its disengaged position by the upper portion of the cam drive 21 and fitting 15 on shaft 16 moves into engagement with ring 20 of the deceleration buffer assembly whereupon rotational and axial movement of shaft 16 will be gradually stopped.

A modified form of the present invention is illustrated in Figs. 3 through wherein a suitable rotary driving mechanism 30, fixed to a stationary supporting structure, as indicated, carries on the end of its rotary shaft a fitting 31. Extending through and fixed at a point midway between its ends to fitting 31 is an arm 32 which carries at each of its ends a target 33 in the form of a relatively thin fiat plate. Each of the targets, adjacent the juncture thereof with the arm 32, is grooved, as

shown at 34 in Figs. 4 and 5, to provide areas of stress concentration. The depth of the grooves is such that when arm 32 is driven at a desired angular velocity, the

stress at the grooved section of the targets, arising from centrifugal force, will approach the fracture stress for the particular material from which the targets are made.

Disposed substantially in the plane of rotation of arm 32 and spaced a predetermined distance from the circular path described by targets 33 during rotation thereof, are a pair of fixed fuzes 35 having their axis, as extended, tangent to the aforesaid circular path. Fixed to a stationary supporting structure, as indicated, and positioned above and below the plane of rotation of arm 32 are two pairs of diametrically opposed target notching devices indicated at 36. As more clearly illustrated in Fig. 4, each target notching device comprises a pair of spaced guides 37 and 37 arranged in planes parallel to the aforesaid plane of rotation. Slidably mounted in said guides for movement in a direction at right angles to the plane of rotation is a notching blade 38 having alfixed thereto a collar 39. A compression spring 40, abutting the collar 39 and guide 37, serves to bias the cutter blade toward the plane of rotation. A latching mechanism, which may comprise a solenoid actuated stop device 41 including a retractable stop member 42, serve to releasably secure the notching blade 38 in its retracted position illustrated by engagement of stop 42 with collar 39. As shown in Fig. 4, the blades of each pair of notching devices are so positioned as to be in alignment with the grooved portions 34 of the targets 33 when the latter move therebetween.

In the operation of the above described modification of the present invention, arm 32 is driven to a desired angular velocity, whereat, as previously described, the stress, arising from centrifugal force acting on the targets 33, will approach the fracture stress of the material from which the targets are constructed. During this period, the notching blades 38 are retained in their retracted position by means of stop devices 29, 41, and 42. Upon the arm 32 attaining the desired angular velocity, solenoid devices 41 are energized whereby to cause stop members 42 to move out of engagement with the collar 39 on their associated notching blades. Compression springs 46 will thereupon cause the notching blades to move into the path of the moving targets and cut notches in the opposite edges thereof. The arrangement is such that the additional notching will cause a sudden brittle fracture of the targets along the apex of the grooves 34 whereupon the targets move in free flight along tangential paths into impact with the fixed fuzes, as shown in Fig. 3. It has been found that the free flight path traversed by the targets is predictable and that by positioning the targets a predetermined distance from the circular path described by the targets prior to their release from arm 32, the conditions of impact between fuze and target may be controlled.

It will be appreciated from the foregoing that in the modification of Figs. 1 and 2 the incidence angle of impact of target and fuze may be varied by varying the angle at which the target is fixed to the rotary supporting arm while in the modifications of Figs. 3 through 5 the incidence angle of impact may be varied by varying the spacing between the fixed fuzes and the circular path traversed by the targets prior to their release from the rotary supporting arm. While the apparatus of this invention will, in actual practice, be operated in a chamber from which the air has been evacuated whereby to provide a vacuum, such chamber forms no part of the invention and has, therefore, been omitted from the drawing for the sake of clarity.

From the above it will be apparent that the present invention provides a novel arrangement for projecting a target into impact with a fixed fuze whereby to permit simplified and more accurate observations of fuze behavior during the impact period.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be undersood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. Controlled impact apparatus comprising a support mounted for rotation about an axis and translation along said axis, a stationary first member fixed at a given radial distance from said axis, a second member carried by said support at said given radial distance from said axis, said support being adapted to be driven to a predetermined angular velocity with said second member moving in a radial plane axially spaced from the radial plane including said stationary member, and selectively operable means for causing axial translation of said support during rotation of the latter whereby to bring said planes into coincidence and cause impact between said members.

2. Controlled impact apparatus comprising a rotary support adapted to be driven at a predetermined angular velocity, a first member fixed to said support for movement' along a circular path during rotation of said support, a stationary second member fixedly disposed in a predetermined position relative to said path, and selectively operable means for effecting release of said first member from said support during rotation of the latter and at such a point along said circular path that said first member will move in free flight into impact with said second member.

3. Apparatus according to claim 2 wherein said last mentioned means comprises a blade normally disposed out of said path and selectively movable into said path whereby to notch said first member and induce brittle fracture thereof.

4. Apparatus for effecting controlled impact between a first member and a second member, comprising a stationary supporting structure, a shaft rotatably supported on said structure, a radial arm fixed to said shaft, means for fixing said first member to said arm whereby when said first member is fixed to the arm and the latter is rotated, said first member will describe a circular path, means for fixing said second member to said structure in a predetermined position relative to said path, and means for eflfecting release of said first member from said arm at such a point along said path that said first member will move in free flight into impact with the second member when the latter is fixed to said structure.

5. Apparatus according to claim 4 wherein said last mentioned means comprises a cutter blade mounted on said structure and selectively movable into said path for notching said first member during rotation of the latter whereby to cause a brittle fracture therein and separation thereof from the arm.

6. Apparatus for effecting controlled impact between a stationary member and a movable member, comprising a support mounted for rotation about an axis, an arm. fixedly attached to said support and extending radially outwardly therefrom, said movable member being rigidly attached to the extending end of said arm, said support being adapted to be rotated so that said movable member attached thereto attains a predetermined velocity in a circular path, said stationary member being fixed at a point a given distance from the circular path of movement of said movable member, and means operable to cause movement of said movable member from said circular path to the fixed point at which said stationary member is positioned, whereby to cause impact between said members.

7. Apparatus according to claim 6 in which the support is mounted for rotation about a vertical axis.

8. Apparatus according to claim 6 in which the point to which the stationary member is fixed is at the same radial distance from the axis of rotation of the support as is the path of the movable member but is axially spaced therefrom, and in which said means operable to cause translation of the movable member comprises selectively operable means for causing axial translation of said support during rotation thereof whereby to cause the movable member to have impact with the stationary member.

9. Apparatus according to claim 8 wherein said translation causing means includes a rotary cam carried by said support.

10. Apparatus according to claim 9 having means for driving said support and releasable clutch means selectively operable to connect said rotary cam and said driving means when said arm carrying said movable member is rotating in a path axially spaced from the point at which the stationary member is fixed, said clutch means being released upon axial translation of said support to a position Where the path of rotation of the movable member includes said point.

References Cited in the file of this patent UNITED STATES PATENTS 1,662,629 Baden-Powell Mar. 13, 1928 1,825,882 Mauney Oct. 6, 1931 2,188,898 Haskell et al. Feb. 6, 1940 2,300,361 Reynolds Oct. 27, 1942 2,388,246 Berger Nov. 6, 1945 2,465,437 Engelhardt Mar. 29, 1949 

